Combustible gas detection using MQ-9 gas sensor

The EzloPi smart devices provide automation through simple, customizable use with our open-source EzloPi platform, making daily life easier and improving human-machine interactions.

Before moving into this example, it is very important to know about the device registration, provisioning and converting the ESP32 device into an EzloPi device along with knowledge of Web Flasher, MiOS Mobile Application for Android/iOS and the MiOS Web Application.

The following project integrates the MQ-9 combustible gas sensor with the EzloPi device for creating a robust and efficient gas monitoring system. The MQ-9 sensor is renowned for its accuracy in detecting various gases, making it an ideal choice for environmental monitoring. The MQ-9 gas sensor has high sensitivity to Carbon Monoxide, Methane and LPG. The sensor can be used to detect different combustible gases, it is low cost and suitable for different applications.

By interfacing this sensor with the EzloPi device, real-time gas concentration data can be easily accessed and monitored remotely. This project holds significant potential for applications in smart homes, industrial settings, and environmental monitoring, contributing to enhanced safety and awareness.

The following components are required for interfacing with the EzloPi device:

• ESP32 as an EzloPi smart device.
• MQ-9 LPG combustible gas sensor.

The wiring diagram for the ESP32 30 pin is represented as below:

The following connections are made in order to complete the circuit setup:

From ESP32 to the MQ9 Combustible Gas Sensor:

Set up your device/hardware by visiting config.ezlopi.com

2. Log in using the credentials which you just set earlier while signing up.

3. Now, click on the Connect Device button and a pop-up window will appear.

4. Now, select COM Port to which your ESP32 device is connected. In our case, the COM3 port is used.

Click Connect.

5. If you are new to this and it's your first time configuring, select Create new Device ID. Enter Wifi SSID and Wifi Password.
6. In the Device Configuration, tab click on Other.

7. A window will open for inputting the following parameters:

• Set a device name of your choosing. In our case, we set it to MQ9.
• Set Device subtype to MQ9 LPG Flammable Gas Sensor.
• Check the box of GPIO 1.
• Set GPIO 1 to 25.
• Check the box of GPIO 2.
• Set GPIO 2 to 33.
• Then Click Apply Button.
• After clicking the apply button you can see a table of your setting in the device configuration tab.
• Press the Flash Device button.

8. A window will appear on the bottom right side of the screen displaying “Please press BOOT button while flashing begins.”

9. Hold the BOOT button down until the next window appears on the bottom right side of the screen which says “Installation prepared. Please release the boot button now.”

10. Release the BOOT button from your ESP32 when this pop-up on the bottom right window appears.

11. After some time, a popup will appear saying Device Flashed Successfully! This means that your device has been set up successfully.

You can download the MIOS Android app from the Google Play Store and Apple App Store.

1. After downloading the app, proceed to install the application and open it.

2. Using the MIOS mobile application, create a new Ezlo Cloud account using the sign-up option. If you already have an account, you may proceed to log in.

3. After successfully logging in, you will be able to see the number of controllers connected such as a lamp, fan, or any other device in the MiOS app. Tap on any controller of your desired ID:

4. You will be able to see the status of your controller whether it is online or offline. Access the device dashboard, and tap the device. The following view of the dashboard will appear:

5. After opening the MiOS mobile dashboard, you see the tile of your connected device. The MQ9 tile will reflect the concentration readings of the LPG gas as shown above.

1. After configuring the controller with the EzloPi web flasher, head to ezlogic.mios.com

2. Use the same credentials to log in that you used for configuring the controller with the web flasher.

3. After opening the MiOS web dashboard, you see the tile of your connected device. The MQ9 tile will reflect the concentration readings of the LPG gas as shown above.